The transendothelial transport of macromolecules and proteins is mediated by intracellular vesicles which shuttle nolecules between blood and tissue. Differential vesicular transport is presently unknown. The purpose of this research project is to establish the differential ingestion rates of the major serum proteins and to determine the relative predominance of carbohydrate mediated vesicular transport. In order to pursue these studies, we have developed procedures for the isolation of continuous capillary endothelial cells. In addition, we have developed procedures for the precise quantitation of vesicular ingestion in endothelial cells using fluorescently labelled proteins as ingestion markers. The long-term goal of these studies is to establish the mechanism and molecular specificty of transendothelial vesicular transport in both normal physiologic and pathophysiologic condition. A knowledge of the conditions which influences vesicular transport in capillaries will aid in understanding the inter-relationship between growing tumors and their vascular supplies, and the increased leakiness of the diabetic microcirculation.